The invention relates to driveway truck restraints for blocking the path of travel of an ICC bar at the back of a truck on a driveway in front of a loading dock, to block forward travel of the truck away from the loading dock.
Driveway truck restraints are known for engaging the truck's ICC bar, also known as the rear impact barrier or underride guard or rear impact guard. Interstate Commerce Commission regulations dictate a maximum height of 31 inches of the ICC bar above grade, i.e. above the top of the driveway, for older trucks, and a maximum height of 22 inches for newer trucks. Truck restraints must thus have a height in a retracted or release position less than the height of the ICC bar, to permit forward travel of the truck away from the loading dock. Preferably, the retracted height of the restraint is substantially less than the ICC bar, to accommodate various conditions such as underinflated tires, trucks having an air ride suspension which may lower the truck during loading/unloading, a sloped driveway leading to the loading dock, etc. To accommodate these conditions, low profile restraints are known in the prior art, having a height of about 10 inches or less above grade in the retracted release position.
In typical installations known in the prior art, the restraint housing has a hollow vertical column encasing a ram bar and supporting and guiding the ram bar for upward and downward movement into and out of the path of the ICC bar. During installation, a hole is cut in the driveway, and the subgrade therebelow is excavated to allow insertion of the column downwardly thereinto, followed by pouring of concrete into the excavation and the hole in the driveway around the column, such that the column is mounted in cast-in relation. The column extends downwardly to a depth as far as 42 inches below the top surface of the driveway. At this depth, various underground objects may be encountered, including drain tiles, drainage pipes, electrical utility lines, etc. The cast-in restraint housing is not removable nor replaceable nor reusable without destroying a portion of the driveway therearound.
The present invention arose during continuing development efforts directed toward improved driveway truck restraints.
In one aspect, the present invention provides a low profile restraint not only above ground but also below ground. The underground depth requirement is reduced to a range of about 19 to 27 inches below the top surface of the driveway, rather than the above noted 42 inches.
In another aspect, installation cost is reduced, both material and labor, by reducing the noted depth and/or extent of excavation, and by eliminating the need for concrete filling the noted excavation and hole in the driveway.
In another aspect, the restraint housing is readily removable, replaceable and reusable without destroying the driveway or portions of the driveway around the housing. This is desirable to enable the restraint to be mounted at a different location in the future, to meet changing needs, such as a relocated loading dock position, or to be eliminated altogether, for example if the loading dock or building is to be used for a different purpose.
In another aspect, the present restraint is immediately usable, without waiting for concrete to cure.
In a further aspect, a water dam is provided for protection of a cable pulley system. In some implementations, the ram bar cavity is filled with anti-freeze solution. The dam prevents casual water from diluting such anti-freeze solution.
The present invention further provides improvements in ease of installation and in flexibility of use.